[英]Confidence interval and p.values for difference between means with summarize function and tidyverse
I am trying to figure out how to turn a data frame from long to wide, while grouping by two variables (diamond cut and colors D and F from diamonds df) and summarizing some key features of the data at the same time.我试图弄清楚如何将数据框从长到宽,同时按两个变量(钻石切割和颜色 D 和 F 来自钻石 df)分组并同时总结数据的一些关键特征。
Specifically, I am trying to get the difference between two means, 95% CI and p-values around that difference.具体来说,我试图获得两个平均值之间的差异,即 95% CI 和围绕该差异的 p 值。
Here is an example of my desired output table (in red is what I am trying to accomplish). 这是我想要的输出表的一个例子(红色是我想要完成的)。
Sample code below, showing how far I've gotten:下面的示例代码,显示了我已经走了多远:
library(tidyverse)
# Build summary data
diamonds <- diamonds %>%
select(cut, depth, color) %>%
filter(color == "F" | color == "D") %>%
group_by(cut, color) %>%
summarise(mean = mean(depth), #calculate mean & CIs
lower_ci = mean(depth) - qt(1- 0.05/2, (n() - 1))*sd(depth)/sqrt(n()),
upper_ci = mean(depth) + qt(1- 0.05/2, (n() - 1))*sd(depth)/sqrt(n()))
# Turn table from long to wide
diamonds <- dcast(as.data.table(diamonds), cut ~ color, value.var = c("mean", "lower_ci", "upper_ci"))
# Rename & calculate the mean difference
diamonds <- diamonds %>%
rename(
Cut = cut,
Mean.Depth.D = mean_D,
Mean.Depth.F = mean_F,
Lower.CI.Depth.D = lower_ci_D,
Lower.CI.Depth.F = lower_ci_F,
Upper.CI.Depth.D = upper_ci_D,
Upper.CI.Depth.F = upper_ci_F) %>%
mutate(Mean.Difference = Mean.Depth.D - Mean.Depth.F)
# Re-organize the table
diamonds <- subset(diamonds, select = c(Cut:Mean.Depth.F, Mean.Difference, Lower.CI.Depth.D:Upper.CI.Depth.F))
#Calculate the CIs (upper and lower) and p.values for mean difference for each cut and insert them into the table.
?
I think I am supposed to calculate the CIs and p-values mean difference in depth between colors D and F at some point before I summarize, but not exactly sure how.我想我应该在我总结之前的某个时间计算 CI 和 p 值平均颜色 D 和 F 之间的深度差异,但不完全确定如何。
Thanks for the input.感谢您的投入。
To get comparisons of means (with t-tests) for D and F colours across different values for cut
, this is what you would need to do:要在cut
不同值之间比较 D 和 F 颜色的均值(使用 t 检验),您需要执行以下操作:
library(broom)
diamonds %>%
filter(color %in% c("D", "F")) %>%
group_by(cut) %>%
do( tidy(t.test(data=., depth~color)))
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.